Vince Hileman - San Jose CA
Steven J. Furuta - Santa Clara CA
Clifford B. Willis - Tracy CA
Robert J. Lajara - San Jose CA
James Testa - Mountain View CA
Sun Microsystems, Inc. - Mountain View CA
A modular circuit board placement system is disclosed that provides for flexible placement of daughterboards, for minimal bus signal path lengths between motherboard and daughterboards, and for ease of installation and removal of daughterboards. The placement system employs dual height bus connectors, a stepped back panel, easy to engage and disengage dual height card retainers, filler panels that also function as module mounts, and multipurpose circuit card handles that facilitate removal of daughterboards. Daughterboards have a two-tier staggered arrangement above the motherboard. Each daughterboard has a signal transfer end that electrically connects to the motherboard through one of the dual height bus connectors, and a back panel connector end that couples to the back panel with an accessory connector or with a filler panel that functions as an electromagnetic interference shield. Dual height card retainers that require no tools to operate function as retaining means to prevent daughterboards from working lose from bus connectors during shipment. Multi-purpose circuit card handles are employed to facilitate installation and removal of daughterboards during field upgrade and field service, or to function as circuit card retainers in systems having only one tier of daughterboards.